Massage chairs are more and more popular for health reasons, which are not only used in homes, but also popular in many public places, such as amusement places.
Generally, the massage chair has a dynamic mechanism for providing the functions of massage, beating, vibration, etc. The dynamic mechanism is connected to a sliding unit for moving upwards and downwards. The sliding unit is installed between two tracks. The sliding unit is driven by a motor or a screw rod. In the prior art, the top view of the tracks is like a U shape. The wheels between the tracks have gaps to the lateral plates of the tracks so that the wheels move smoothly. However when the dynamic mechanism makes a dramatic action, noise will generate due to the wheels colliding with the tracks continuously. This will affect the users and the users will feel that the structure of the massage chair is not firm. This problem is existed almost all the massage chairs.